Inspector General of Police Benazir Ahmed has described the Kalabagan rape as a "complete crime".
"It was murder and rape, but both the victim and the accused are children according to our law," he said on Monday.
He warned of tougher action against juvenile gangs while addressing a programme at the Rapid Action Battalion headquarters in the capital.
The police chief talked about the difficulties police face while performing their duties under present laws, especially in cases where children are involved in criminal activities.
Benazir said human rights activists and non-governmental organisations (NGOs) had played a role in changing many laws by creating a huge buzz and those modern laws had created big challenges for police.
"We must be aware of whether we are causing any trouble in the country through formulation of these modern laws."
"The current law says when a child accused of criminal activities is taken to a police station, there should be a probation officer there. But the number of probation officers in the country is inadequate," said Benazir.
He said there are not enough juvenile courts and the country also lacks juvenile correction centres.
The police chief urged human rights and child rights activists to address these issues and organise awareness campaigns.
Benazir said newspapers are flooded with reports on juvenile gangs and social movements are necessary to check them.
He emphasised parental control, saying, "Why did you (parents) give birth to children if you cannot take their responsibility?"
Benazir said it is the responsibility of families to give moral education to children.
"It is their social and religious duties as well."